List1 = [21,25,21,23,22,20]
List1.append(31)
print(f"列表为：{List1}")
List2 = [28,33,30]
List1.extend(List2)
print(f"列表为：{List1}")
out = List1.pop(0)
print(f"取出元素{out}，列表为：{List1}")
out = List1.pop(7)
print(f"取出元素{out}，列表为：{List1}")
find=List1.index(31)
print(f"找到下标31位置为{find}")